Galling, is a form of severe adhesive wear or seizing which can occur when two metals are in close contact and can move against each other and are under sufficient load to allow the transfer of material. It is also sometimes known as cold welding.
A classic example of galling is when the threads of nuts and bolts are forced together.
In severe cases, galling can result in the seizure of the metal components in contact with each other.
Galling can be prevented, or minimised, at the design stage design, by adjusting tolerances and the hardness and microstructure of the metals to be in contact, as well as improving the surface finish of the metal.
Alternatively, once in place, Dry film lubricants can be used to protect the metals.